The best results I've seen thus far are when I'm feeding a 1-3-2 NPK ratio during the last 2/3rds of flower. So if a PK booster 'boosts' you near a 1-3-2 ratio then I'd say it's something you should look into further. Though I know for a fact that there are products out there that give you a 1-3-2 off the bat which in my experience eliminates the need for any extra NPK jazz.
Besides all that, I've found that, that same 1-3-2 ratio is the best for long term host plant maintenance and good cuts. I use Jack's Bloom Booster, about 3/4 strength every couple of weeks or so. Enough N for growth and the P and K levels make for firm stems and easy rooting.
Might be a useful observation to someone, might not be. YMMV
Wet